This project involves the analysis of a variety of complex traits, including data collected by the Genetic Studies Section as well as data collected by many different collaborating units. Analysis consists both of utilization of standard genetic, statistical, and epidemiologic methods, as well as the development of novel methods on an "as-needed basis" specific to the type of data in question. In addition, Section personnel provide consultation and support for various investigators, both intramural (within the NIAMS and elsewhere in NIH) and extramural, who are interested in assessing the genetic component of diseases. We provide guidance to other investigators, or directly design and execute studies to (1) assess familial aggregation of disease, (2) evaluate the statistical evidence for linkage relationships between disease and genetic markers, (3) assess the relative risks of various environmental components to the development of disease, and (4) provide software support for genetic analysis programs, either those available publically or those we develop in the Section. In the past year, Section personnel have worked on several projects, including an assessment of familial relationships between individuals in a restricted population with rheumatoid arthritis (the Pima Indian population on the Gila River Reservation near Phoenix, AZ); assessment of familial aggregation of various autoimmune disorders, including rheumatoid arthritis, dermatomyositis, and other related disorders; linkage analysis in optic atrophy, Charcot-Marie-Tooth disease, generalized atrophic benign epidermolysis bullosa, cystinuria; design of a genetic epidemiologic study of severe cystic acne utilizing a unique database of individuals in whom the use of Accutane was originally tested for treatment of this disease; and analysis of data from an epidemiologic study of an intronic polymorphism in the XPC locus to determine if there was an association with longevity or specific malignant outcomes. Each of these collaborative studies allowed Section personnel to develop novel approaches to questions about hereditary disease, and provided much needed assistance to other organizations who lacked personnel with the expertise to address their scientific questions.